1. Field of the Invention
The invention relates to a stereophonic audio signal processing arrangement comprising:
signal processing means, including a stereo enhancement circuit for processing a stereo input signal, PA1 signal amplifying means for amplifying a stereo output signal supplied by the signal processing means, PA1 said stereo enhancement circuit comprising: PA1 generating a stereo output signal having an enhanced stereo image from the stereo input signal, and PA1 controllably combining the stereo input signal and the stereo output signal to provide a processed stereo output signal.
first means having a first and a second input for receiving a left channel and a right channel signal of the stereo input signal and a first and a second output for supplying a left channel and a right channel signal of a stereo signal having an enhanced stereo image, and PA2 second means for controllably combining the stereo input signal and the stereo output signal of the first means for varying the stereo image enhancement.
The invention further relates to a stereophonic audio reproduction system including such a stereophonic audio signal processing arrangement, and left channel and right channel loudspeakers for reproducing the amplified stereo signal supplied by the signal amplifying means.
The invention also relates to an audio-visual reproduction system including such a stereophonic audio reproduction system, a cabinet in which a picture display screen and the left channel and right channel loudspeakers are installed.
The invention relates to a stereo enhancement circuit.
The invention also relates to a method for enhancing a stereo image of a stereo input signal, comprising the steps of:
2. Description of the Related Art
Such an arrangement, such systems and such a circuit are known from the European Patent Application EP-A 664661, corresponding to U.S. patent application Ser. No. 08/371,187, filed Jan. 1, 1995, now U.S. Pat. No. 5,742,687. In the known arrangement the enhanced stereo signal can be mixed with the input stereo signal, for example, in a ratio (1-.alpha.):.alpha.. By varying a between 0 and 1, the amount of stereo image enhancement can be varied from conventional, or normal, stereo to fully enhanced stereo. A drawback of the known stereo image enhancement is that the amplitude of the enhanced stereo signal can be more than 10 dB larger than the amplitude of the normal, unenhanced, stereo signal, even though the loudness of the resulting acoustical signals is perceived as substantially the same. At high signal levels, this larger amplitude of the enhanced stereo signal may give rise to distortion in an amplifier following the arrangement.